This invention relates to a lubricating device for the power device of an inboard/outboard unit and more particularly to an improved lubricating system for a marine outboard drive.
In one well known type of marine outboard drive, there is Provided an outer casing that is adapted to be mounted on the transom of a watercraft and which includes an input shaft that is driven by the engine, a drive shaft that rotates about a generally vertically extending axis and which is driven by the input shaft from a first transmission. The lower end of the drive shaft is drivably coupled to a propulsion device such as a propeller through a second transmission. Normally, the outer casing defines a lubricant sump which surrounds the second transmission and which lubricates certain components of the outboard drive.
Although this type of arrangement is particularly advantageous, the tendency is for the lubricating oil to become quite hot because of its combined function of lubricating and cooling the components. Particularly, where the lubricant is above the water level, it can reach high temperatures such as 100.degree. C. and this can cause certain problems such as corrosion of rubber seals, paint coatings and deterioration of the oil.
It is, therefore, a first object of this invention to provide an improved lubricating device for a marine outboard drive wherein the lubricant will be circulated within the outboard drive for combining the lubricating functions and also for cooling the lubricant.
It is a further object of this invention to provide an improved pressure lubricating system for a marine outboard drive wherein the lubricating pump is driven from the input shaft and draws lubricant from the lubricant sump, delivers it to the various components to be lubricated and returns it to the sump.
In conjunction with marine outboard drives of this type, it has recently been proposed to construct the arrangement in such a manner that the simple reversal of a bevel driving gear on the input shaft from one side to the other of a driven bevel gear at the upper end of the drive shaft is effective to achieve counterrotation. A highly useful construction in which this type of reversal can be achieved is shown in the copending application of Hayasaka Kenichi, entitled "Propulsion Unit For Inboard-Outboard Motor", Ser. No. 252,683, filed Oct. 3, 1988, and assigned to the assignee of this invention. However, when a lubricating system having a driven pump is employed with such a reversal mechanism, it is desirable, in order to maintain the advantages of simplicity of that type of system, to insure that the driving pump will be driven in the same direction regardless of the direction in which the drive shaft is driven.
It is, therefore, a still further object of this invention to provide an improved arrangement for driving the lubricating pump of an inboard/outboard unit.
It is a further object of this invention to provide an improved lubricant pump driving arrangement for an inboard/outboard engine wherein the reversal of the drive shaft may be easily obtained and wherein the lubricant pump is always driven in the same direction regardless of the direction of rotation of the drive shaft.